Abstract: A method and means for transmitting a waveform of mixed frequency content over a transmission line in a way to minimize distortion are disclosed. The specific application relates to a bifrequency or biphase encoded binary data transmission system. Distortion is minimized by reducing the low frequency content of the signal which results in less phase shift error per unit distance. This is accomplished by distinguishing bits encoded at the lower frequency of the bifrequency encoded data and then reducing the amplitude of the low frequency bits to a relatively small fraction of their initial amplitude during the latter portion of each of the bit periods.